That belief is why they are generally discounted when discussing Chinas naval capabilities, however I believe we will see them used in a much more offensive, and persistent manner in the future.
1. Persistence, in general, is determined by (1)autonomy and (2)seaworthiness (incl. maximum sea state when weapon usage is permitted).
022 is a really small boat in the end, with a small crew, little internal volume(hull form doesn't help), and a lot of single-purpose armament weight for its class.
2. Sensor suite of 022 is fairly basic, point in using it for patrol duties far from bases is honestly lost to me. There isn't much they can detect that maritime militia can't.
3. Light, high-performance diesel engines (almost mandatory for such applications) often have relatively low service life. Simple training for such usage will gradually wear down the ships. Aluminum hull is a major suspect here, too.
4. Continued presence exposes vessels to the possibility of attack (and substantially complicates their defense by third assets). 022s on their own are vulnerable to literally anything. And if you deploy other persistent assets to cover them - point in insisting on having 022s at sea is honestly lost.
5. They can indeed be operated from SCS island base, another type of a forward base, or simply from a tender(preferably in some sort of calm water). This is still the same thing, however - they are not on their own, and can return at will. But their capability in hostile littoral appears to be very secondary to me.
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All in all - they're better left to what they were originally designed to do.